10. The Original ‘Wicked’ Witches Have Both Guest Starred

Tony winners Idina Menzel, who plays Vocal Adrenaline’s scheming coach and Rachel’s birth mother, and Kristen Chenoweth, who plays the uber-talented McKinley alum (and alcoholic) April Rhodes, have both made multiple appearances on “Glee.” Menzel and Chenowith were cast as Elphaba and Glinda, respectively, in the original Broadway production of “Wicked.”

9. Dianna Agron Was Cast Last Minute

The day before shooting the pilot, the role of head cheerleader Quinn Fabray still hadn’t been cast. Dianna Agron auditioned for the part the night before filming began and won the role. In an interview with Rolling Stone, creator and producer Ryan Murphy explained that Agron wasn’t exactly what he had in mind. “When we cast Dianna as Quinn, she ruined the part for me. She was supposed to be the Cybill Shepherd, ‘Last Picture Show,’ so to speak, but she humanized it. She can cry at the drop of a hat. So now her character has a conscience, a soul, and great vulnerability.”

8. Jane Lynch Can Sing

Yes, that is Jane Lynch’s voice in the “Physical” reboot with Olivia Newton-John and the shot-for-shot video remake of Madonna’s “Vogue.” But that’s not the first time fans have sampled the funnywoman’s vocal stylings; she sang and played the guitar in the 2003 mockumentary “A Mighty Wind.”

7. Mark Salling Hated His Mohawk

Puck may have won hearts with his signature hair, but the 27-year-old actor didn’t love his trademark look. “I’m so over the mohawk, I’m not gonna lie,” he revealed. “I hate the mohawk.” Salling sported the haircut during his audition and throughout “Glee’s” first season, until his character shaved if off in the lead up to the finale.

6. Lea Michelle (Rachel) and Jenna Ushkowitz (Tina) Go Way Back

The pair met when they were eight years old, and both actresses appeared in the Tony-winning Broadway musical “Spring Awakening” – but at different times.

5. Kurt Wasn’t Supposed to Be in ‘Glee’

The part of Kurt was written specifically for actor Chris Colfer after he was passed over for the part of wheelchair-bound Artie.

4. Amber Riley Was an ‘American Idol’ Reject

When she was 17, Amber Riley tried out for “American Idol” but was turned down by the producers. Now, the 24-year-old is belting out tunes for a living as powerhouse singer Mercedes.

3. Cory Monteith Was a Wal-Mart Greeter

Before he was roaming the halls of William McKinley High as football hunk Finn Hudson, Cory Montheith worked at a Wal-Mart in Canada as a guest greeter.

2. Matthew Morrison Was One of the Popular Kids

Will Schuester may not have had the best high-school experience, but, in real life, Morrison was captain of his school’s soccer team and cemented his popularity by being elected class president and prom king.

1. Lea Michele Slapped a Casting Director

During her audition, Lea Michele reached across the table without hesitation and slapped one of the casting directors, who was reading the part of Finn (the original pilot script called for a slap between the two characters). When the other casting directors erupted with laughter, Michele told them “This isn’t comedy — that was my sad face! Now I’m going to do it again and you’re all going to cry.”